Place clams and 1/4 cup water in a large heavy pan. Cover and simmer just until clams pop open (5 to 10 minutes). When cool enough to handle, remove clams from shells and set aside (save a few clams in shells for garnish, if you wish). Strain clam broth through a piece of dampened muslin to remove grit; reserve broth. Cook linguine in a large kettle of boiling salted water according to package directions until al dente; drain well. While linguine cooks, place butter and oil in a wide frying pan over medium heat. When butter is melted, add onion and cook, stirring often, until soft. Mix in garlic, wine, and strained clam broth. Bring to a boil, stirring occasionally, and cook until liquid is reduced by about half. Add clams, season with salt and pepper to taste, and stir in parsley. Arrange linguine on a warm serving platter. Spoon hot sauce over linguine. Garnish with reserved clams in shells, if you wish.